(a) Field of the Invention
This invention relates to a storage rack used for holding pallets of stored goods and more particularly, but not by way of limitation, to a storage rack having a flexible moment frame. The flexible moment frame is capable of sufficient flex or float during an earthquake to prevent collapse of the frame and damage to the stored goods received on pallets.
(b) Discussion of Prior Art
Earthquakes are daily occurrences around the world and caused by a release of energy in the earth's crust. This release of energy creates seismic waves, measured using seismometers. An earthquake of a magnitude 3 or less is almost imperceptible. But, an earthquake of a magnitude from 5 to 7 and greater can cause great damage to building structures. The subject invention is designed to address potential damage to stored goods in a building when a seismic, lateral force is applied, caused by an earthquake.
With the advent of large forklifts capable of raising pallets with goods thereon and placing the pallets on storage racks 12, 18, 24 feet and higher, the tall storage racks are now subject to swaying, collapsing or toppling over during a severe earthquake, thus causing damages to the stored goods.
In U.S. published applications 2006/0237378 to Pellegrino et al. and 2002/0117462 to Hung, two different types of flexible storage racks are disclosed for seismic vibration absorption and dissipation. In one of these applications, a vibration isolator is installed at the base of the rack along with added diagonal bracing for stiffening the rack frame. These two storage racks are complex in design with additional frame and base structure not required in the subject invention.
The subject invention is simplistic in design with unique structural engineering features and advantages not found in previous large and tall metal storage racks used inside a building or outside the building.